JP3282633B2 - Method for producing quaternary ammonium hydroxide aqueous solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-purity aqueous solution of quaternary ammonium hydroxide used for a developing solution of a positive resist or a cleaning solution for a substrate in an LSI or LCD manufacturing process, or a polycarbonate resin. The present invention relates to a method for producing a quaternary ammonium hydroxide aqueous solution used for producing a polymerization catalyst, a zeolite catalyst, and the like.

[0002]

2. Description of the Related Art A quaternary ammonium hydroxide aqueous solution has a wide range of uses and is currently produced in large quantities. In particular, in recent years, an inexpensive and high-purity quaternary ammonium hydroxide aqueous solution has been demanded.

Conventionally, the following method has been used as a method for producing quaternary ammonium hydroxide.

1) A method of reacting a trialkylamine with an alkyl halide to synthesize a quaternary ammonium halide, and electrolyzing the quaternary ammonium halide to produce a quaternary ammonium hydroxide.

2) A quaternary ammonium organic carboxylate is synthesized by reacting a trialkylamine with an organic carboxylic acid ester, and the quaternary ammonium organic carboxylate is electrolyzed to produce a quaternary ammonium hydroxide. how to. (Japanese Patent Laid-Open No. 60-100690)

3) A trialkylamine is reacted with a dialkyl carbonate to synthesize a quaternary ammonium salt, and the quaternary ammonium salt is electrolyzed.
A method for producing quaternary ammonium hydroxide.

In the above-mentioned method (1), harmful and corrosive halogen ions and halogen gas are generated at a high concentration in the anolyte during the electrolysis step, causing troubles such as corrosion of the anode itself or the material of the apparatus. Occurs. Further, when producing a high-purity quaternary ammonium hydroxide aqueous solution, during electrolysis, halide ions migrate to the cathode side through an ion exchange membrane, or due to an increase in impurities due to corrosion, etc. It has a drawback of lowering the purity. The above (2)
In the electrolysis process, the organic acid ions are generated in the electrolytic process, and the anode itself is corroded. In order to electrolytically oxidize the formate ions to harmless carbon dioxide gas, a large amount of electricity is required. Have a point. Also, when producing a high-purity quaternary ammonium hydroxide aqueous solution, at the time of electrolysis, the organic acid ions move to the cathode side through the ion exchange membrane, or
There is a disadvantage that the purity is reduced due to an increase in impurities due to corrosion. The production method (3) uses a dialkyl carbonate as a raw material, but is not suitable for producing an inexpensive quaternary ammonium hydroxide aqueous solution because the dialkyl carbonate is expensive.

Further, since the dialkyl carbonate is produced from phosgene and an alcohol, a chlorine compound may be mixed into the dialkyl carbonate, which is not preferable for producing a high-purity quaternary ammonium hydroxide aqueous solution. . As described above, the conventional production method has many problems, none of which can be said to be a sufficient production method, and a method of producing an inexpensive and high-purity quaternary ammonium hydroxide aqueous solution is desired. I have.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned various problems of the conventional method and provides an inexpensive and high-purity method for producing a quaternary ammonium hydroxide aqueous solution. .

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above various problems in the prior art, and reacted trialkylamine and carbamate in the presence of a polar solvent. Then, water is added and heated to synthesize a quaternary ammonium inorganic acid salt, or a trialkylamine and a carbamate are reacted in the presence of water to synthesize a quaternary ammonium inorganic acid salt. The present inventors have found a novel method for producing a quaternary ammonium hydroxide aqueous solution by electrolyzing a quaternary ammonium inorganic acid salt to obtain quaternary ammonium hydroxide, and have accomplished the present invention.

The quaternary ammonium hydroxide in the present invention is represented by the following formula (1).

[0012]

FIG. (In the formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different and represent an alkyl group having 1 to 3 carbon atoms.)

The compound represented by the above general formula is specifically exemplified by tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldipropyl Examples include ammonium hydroxide, monomethyltriethylammonium hydroxide, and monomethyltripropylammonium hydroxide. Among them, tetramethylammonium hydroxide (TMAH) is preferable.

The trialkylamine in the present invention is represented by the following formula (2).

[0015]

FIG. 2 (In the formula, R ₁ , R ₂ and R ₃ may be the same or different and represent an alkyl group having 1 to 3 carbon atoms.)

Specific examples of the compound represented by the above general formula include trimethylamine, triethylamine, tripropylamine, dimethylethylamine, dimethylpropylamine, monomethyldiethylamine, monomethyldipropylamine, diethylpropylamine and the like.

The carbamic acid alkyl ester in the present invention is represented by the following formula (3).

[0018]

FIG. 3 (Wherein R ₄ represents an alkyl group having 1 to 3 carbon atoms;
₅ and R ₆ may be the same or different and represent a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. )

The compounds represented by the above general formulas are, specifically, carbamic acid methyl ester, carbamic acid ethyl ester, carbamic acid propyl ester, N-methylcarbamic acid methyl ester, N, N-dimethylcarbamic acid methyl ester, Examples include N-methylcarbamic acid ethyl ester, N, N-dimethylcarbamic acid ethyl ester, N-methylcarbamic acid propyl ester, and the like.

According to the present invention, a trialkylamine is reacted with a carbamate in the presence of a polar solvent, and then water is added and heated to synthesize a quaternary ammonium inorganic acid salt. A method for obtaining a quaternary ammonium (hereinafter referred to as method A), and a method of reacting a trialkylamine with a carbamate in the presence of water to synthesize a quaternary ammonium inorganic acid salt, and then electrolyzing the quaternary ammonium hydroxide. There is a method of obtaining secondary ammonium (hereinafter referred to as method B).

In the above methods A and B, the amount of the carbamic acid ester or trialkylamine to be used is appropriately selected depending on the kind of the carbamic acid ester or the trialkylamine to be used, the reaction conditions and the like. Typically, the molar ratio of the carbamate to the trialkylamine is in the range of 0.05 to 20, preferably 0.1.
Used in the range of 10 to 10.

In the methods A and B, water is indispensable, and the amount of water to be used may basically be at least the theoretical amount to the carbamic acid ester or the trialkylamine, but is too large. It takes a lot of time for separation and removal after the reaction, which is not economically feasible.

In the method A, examples of the polar solvent used include alcohols such as methanol, ethanol and propanol, acid amides such as N, N-dimethylformamide, and nitriles such as acetonitrile. The amount of the polar solvent used is 0.5 to 2 with respect to the raw material carbamic acid ester or trialkylamine.
The amount is 0 times (weight), preferably 1 to 10 times.

The reaction temperature of the carbamate and the trialkylamine in the method A is usually 50 to 300 ° C.
Preferably it is in the range of 100 to 250 ° C. Method A is
After the reaction, water is added to the reaction product, and the mixture is heated and distilled under reduced pressure, or a gas such as nitrogen, argon, helium, carbon dioxide, or air is blown under heating at 50 ° C. or higher, and unreacted Alternatively, a quaternary ammonium inorganic acid salt can be obtained by removing the polar solvent.

In the reaction of the carbamate with the trialkylamine in the presence of water in the method B, the temperature is as follows:
It is usually in the range of 50 to 300 ° C, preferably 80 to 200 ° C. At this time, the reaction may be carried out in the presence of a polar solvent in addition to water. After the reaction, a quaternary ammonium inorganic acid salt can be obtained by distillation under reduced pressure or by blowing a gas such as nitrogen, argon, helium, carbon dioxide or air to remove unreacted substances, solvents and the like. At this time, if necessary, heating may be performed. The reaction of the methods A and B in the present invention can be carried out by any of a batch system, a semi-batch system and a continuous system.

For the electrolysis of the quaternary ammonium inorganic acid salt obtained by the method A or B of the present invention, usually, an electrolytic cell partitioned into an anode and a cathode by a cation exchange membrane is used. In addition, an electrolytic cell partitioned by two or more cation exchange membranes into an anode chamber, a cathode chamber, and one or more intermediate chambers can be used. As the cation exchange membrane used in the present invention, sulfone groups, those having a cation exchange group such as a carboxylic acid group and the like are preferably used. A styrene-divinylbenzene copolymer having an exchange group may be used.

As the anode used in the present invention, an electrode used in this type of electrolysis, such as a high-purity carbon electrode, a titanium electrode coated with a platinum group oxide such as platinum or iridium, or the like, is used. As the cathode used in the present invention, an electrode used as a cathode in this type of electrolysis, such as stainless steel or nickel, is used. These anodes and cathodes can be used in any shape such as plate, rod, net, and perforated plate.

In the present invention, the electrolysis in the electrolytic cell is performed by applying a DC voltage, and the current density is 1 to 100 A / dm 2, preferably 3 to 50 A / d.
m2. The temperature during the electrolysis is preferably in the range of 10 to 50 ° C. Electrolysis in the present invention is a batch type,
In this case, the concentration of the quaternary ammonium salt of the raw material supplied to the anode chamber may be 1 or less.
-60% by weight, preferably 3-40% by weight.

Further, ultrapure water is supplied to the cathode chamber. At the start of operation, ultrapure water alone has low electric conductivity and does not easily undergo electrolysis. It is desirable to use a liquid containing a small amount of oxide, for example, 0.01 to 5% by weight. Also, it is desirable to perform the electrolysis in an atmosphere of an inert gas such as nitrogen or argon.

Hereinafter, embodiments of the present invention will be described.

【Example】

Example 1 (Method A) 620 g of trimethylamine, 750 g of carbamic acid methyl ester, and 500 g of methanol were stored in a 3000 ml internal volume.
Into a pressure-resistant stainless steel autoclave at 150 ° C
For 5 hours with stirring. 2000 g of water was added to the obtained reaction mixture, heated at 80 ° C., and nitrogen gas was blown at normal pressure to distill off unreacted products and methanol as a solvent, to obtain an aqueous solution of a quaternary ammonium inorganic acid salt. . Water was further added thereto to prepare a 30% by weight aqueous solution of a quaternary ammonium inorganic acid salt.

Next, Nafio was used as a cation exchange membrane.
Using n324 (DuPont fluorinated cation exchange membrane), the electrolytic cell is divided into an anode chamber and a cathode chamber, and a device using a titanium electrode coated with iridium for the anode and a nickel electrode for the cathode is used. Then, a 30% by weight aqueous solution of the above quaternary ammonium inorganic acid salt was circulated in the anode chamber. A 0.5% by weight aqueous solution of tetramethylammonium hydroxide was circulated through the cathode chamber, and a DC current of 20 A / dm2 was applied.
Electrolysis was performed at a temperature of 40 ° C. Electrolysis voltage is 8-12V,
The average current efficiency was 89%, and a 14.1% by weight aqueous solution of tetramethylammonium hydroxide was obtained in the cathode chamber.

Example 2 (Method B) 590 g of trimethylamine, 979 g of methyl N-methylcarbamate, 100 g of methanol, 500 g of water
g was filled into a pressure-resistant stainless steel autoclave having an inner volume of 5000 ml, and heated at 130 ° C. for 5 hours while stirring. Unreacted substances and methanol as a solvent were distilled off while blowing the obtained reaction mixture at 70 ° C. under a normal pressure of nitrogen gas. Water was further added thereto to prepare a 20% by weight aqueous solution of a quaternary ammonium inorganic acid salt.

Next, the same electrolytic cell as in Example 1 was used except that a titanium electrode coated with platinum was used as the anode and a stainless steel electrode was used as the cathode, and the above-mentioned quaternary ammonium inorganic was used in the anode chamber. A 20% by weight aqueous solution of the acid salt was circulated. A 0.3% by weight aqueous solution of tetramethylammonium hydroxide was circulated in the cathode chamber, a direct current of 10 A / dm2 was applied, and electrolysis was performed at a temperature of 30 ° C. The electrolysis voltage is 6-7V, the average current efficiency is 91%, and 9.8
A weight percent aqueous solution of tetramethylammonium hydroxide was obtained.

[0034]

According to the method of the present invention, a high-purity quaternary ammonium hydroxide aqueous solution containing no impurities can be produced at low cost.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-170588 (JP, A) JP-A-60-131985 (JP, A) JP-A-59-193288 (JP, A) JP-A-62 139890 (JP, A) JP-A-64-87796 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25B 1/00-15/08

Claims (2)

(57) [Claims] 1. A reaction between a trialkylamine and an alkyl carbamate in the presence of a polar solvent, followed by addition of water and heating to synthesize a quaternary ammonium inorganic acid salt. A method for producing a high-purity quaternary ammonium hydroxide aqueous solution, comprising producing an aqueous quaternary ammonium hydroxide by electrolyzing an acid salt. 2. A quaternary ammonium inorganic acid salt is synthesized by reacting a trialkylamine and an alkyl ester ether carbamate in the presence of water, and the quaternary ammonium inorganic acid salt is electrolyzed to produce a quaternary ammonium hydroxide. A method for producing a high-purity quaternary ammonium hydroxide aqueous solution, comprising producing ammonium.